The present disclosure relates to an image forming device for forming an image on a sheet.
Conventionally, an image forming device such as a printer or a copier employing the electrophotographic method includes: a photoreceptor drum that carries an electrostatic latent image; a developing device that supplies toner to the photoreceptor drum and visualizes the electrostatic latent image into a toner image; and a transfer device that transfers the toner image from the photoreceptor drum onto a sheet.
Further, an image forming device is known which has a plurality of developing devices in correspondence to color toners of respective colors and in which, for each developing device, two toner containers for supplying supplement toner to the developing device are disposed. Even when one of the toner containers becomes empty, toner from the other toner container can be supplied. Hence, the time over which the image forming device is forced to stop (print incapable time) is shortened. Particularly when a print job involving a large number of sheets to be printed is executed, a situation in which the job is interrupted halfway due to toner shortage can be prevented.
Also, a technique is known of calculating a toner consumption amount of a toner container based on a rotation count of a transport screw arranged in a transport path between the toner container and a developing device.